# Material Energy Balances

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- **Type:** Skill
- **Install:** `agentstack add skill-jskherman-engg-skills-material-energy-balances`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [jskherman](https://agentstack.voostack.com/s/jskherman)
- **Installs:** 0
- **Category:** [Agent Skills](https://agentstack.voostack.com/c/agent-skills)
- **Latest version:** 0.1.0
- **License:** Apache-2.0
- **Upstream author:** [jskherman](https://github.com/jskherman)
- **Source:** https://github.com/jskherman/engg-skills/tree/main/skills/material-energy-balances

## Install

```sh
agentstack add skill-jskherman-engg-skills-material-energy-balances
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# Material and Energy Balances

## Overview

Steady-state helper calculations:

- Component totals from one or more `NAME=amount` entries.
- Conversion and yield from supplied limiting-reactant and product amounts.
- JSON envelopes that make the basis and assumptions explicit.

## Prerequisites

1. `uv` available.

## When to Use

- Summing component amounts from a hand-built stream table.
- Sanity-checking a single stream or component set on a consistent basis.
- Computing rough conversion and yield metrics from known feed/reacted/product
  amounts.

## Don't use for

- Transient (dynamic) balances; the math involves dC/dt and requires a
  state-space approach.
- Rigorous flowsheet convergence; use a simulator.
- Detailed equilibrium / reactor design; this skill is balance-only.
- Full node closure with separate inlet and outlet stream tables.
- Degree-of-freedom counting.
- Selectivity calculations; only conversion and yield are exposed by the CLI.

## Utility Scripts

- `uv run scripts/balance_solver.py component-total --stream A=10 --stream B=5 --output /tmp/total.json`
- `uv run scripts/balance_solver.py reaction-metrics --feed-limiting 10 --reacted-limiting 8 --desired-product 7.2 --theoretical-product 8 --output /tmp/reaction.json`

## Procedure

1. Identify the stream, component set, or reaction metric you need.
2. Keep all values on a consistent molar or mass basis.
3. For totals, pass each component amount as a repeated `--stream NAME=amount`.
4. For conversion/yield, supply limiting-reactant feed, reacted amount,
   desired product amount, and theoretical product amount.
5. Inspect the JSON assumptions before using the result in a larger balance.

## Pitfalls

- Mixing mass and molar basis silently.
- Forgetting recycle streams.
- Reporting "conversion 97%" without naming the key reactant and the
  basis (per pass vs overall).
- Using yield where you mean selectivity (yield is mol product / mol
  reactant fed; selectivity is mol product / mol reactant reacted).
- Computing residuals only in absolute terms; relative residuals
  (residual / inlet) are usually more useful.
- Using mass balance closure to justify a doubtful instrument when
  energy balance also fails to close.
- Counting equations without subtracting redundant ones (a
  total-balance plus all-component balances over-counts).
- Not propagating measurement uncertainty when judging closure ("looks
  closed at 0.5%" might be within instrument noise).

## Fallback Strategies

- If the residual is large but the data is suspect, suggest data
  reconciliation (Crowe's method or similar).
- For dynamic balances, surface that this skill does not cover them.

## Verification

- Run the listed script with representative inputs and an `--output` file when a deterministic calculation is available.
- Confirm the JSON result contains `ok: true`, expected units, and no unhandled warnings.
- Check result magnitudes against the stated assumptions, references, and a hand calculation or known operating range before reporting them.

## References

- `references/workflow.md` — detailed checklist for a node closure.

## Anti-Patterns

- Reporting a balance that does not close as if it does.
- Hiding the basis in the report.
- Using component balances to detect bias without ruling out leakage,
  recycle, or unmeasured purge.

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [jskherman](https://github.com/jskherman)
- **Source:** [jskherman/engg-skills](https://github.com/jskherman/engg-skills)
- **License:** Apache-2.0

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-jskherman-engg-skills-material-energy-balances
- Seller: https://agentstack.voostack.com/s/jskherman
- Browse the marketplace: https://agentstack.voostack.com/browse

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